
PRO CO MONOFACE™ SERIES MODEL
INPUT
DIRECT
OUTPUT
GND
LIFT
MIC SPLITTER
MS-3
MS-3
GND
LIFT
ISO
OUT 2
ISO
OUT 1
MS-3
MS-3
MIC SPLITTER
FEATURES
• Provides 2-Way Split for Low-Z Microphone
• Great for Musicians’ Monitoring and Recording
• ENG Uses Include Press Conferences and Speeches
• Connects with Standard Mic Cables
• High-Quality Transformer-Isolated Output
• Rugged “Uni-box™” Construction for Protection and Shielding
NEUTRIKNEUTRIK
BACK OF UNIT FRONT OF UNIT
DESCRIPTION
The Pro Co Monoface MS-3 Mic
Splitter splits a signal from a lowimpedance microphone (or similar
source) into three outputs, enabling
three microphone preamplifiers to be
fed from one source. Some applications
include musicians’ on-stage
monitoring, live recording, ENG use at
press conferences, and videotaping of
lectures, public speeches, etc. It can
also be used simply as an isolation
transformer for long microphone lines
feeding unbalanced inputs, or for any
audio signal up to 0 dBv (.775 volt).
Transformer isolation in such
situations minimizes interference from
SCR lighting dimmers, radio transmitters and 60 Hz AC power wiring. The
transformer-isolated feeds retain the
advantage of common-mode noise
rejection inherent in the use of
balanced lines.
The MS-3 is fitted with standard
3-pin XLR-type connectors for INPUT,
DIRECT OUTPUT, and ISOLATED
OUTPUTS 1 and 2, so hookup requires
NEUTRIK
NEUTRIK
only standard microphone cables. The
use of the Pro Co MBT-2 transformer
allows the MS-3 to provide two floating,
low-impedance outputs with wide, flat
frequency response, ultra-low distortion,
and no ringing or overshoot to degrade
transient response. The transformer’s
triple electrostatic shields and GND/
LIFT switches provide isolation and
buzz-free operation in virtually any
environment.
The MS-3’s ruggedly constructed
“Uni-box™” enclosure is formed of
extruded aluminum side channels and
16-gauge steel top, bottom and end plates
and is designed to protect switches and
connectors from accidental damage. The
use of steel also provides excellent
magnetic shielding for the transformer
from 60Hz AC hum fields. Top-quality
connectors and switches provide troublefree service even in abusive situations
such as remote broadcast and recording
operations. The uniquely slotted side
channels allow for stacking on top or
strapping side-to-side of virtually any
number of Pro Co Monoface devices
using the Uni-box™ construction.
CONTROLS
INPUT:
Female 3-pin XLR-type connector
accepts signal from low-impedance
(150 ohm nominal) microphone or
similar source.
Input impedance (with 1.0 kohm loads
on DIRECT and both ISOLATED
OUTPUTS): approx. 333 ohm.
DIRECT OUTPUT:
Male 3-pin XLR-type connector wired
in parallel with INPUT provides signal
to feed mixer input.
ISOLATED OUTPUTS:
Male 3-pin XLR-type connectors
provide floating transformer-isolated
low-impedance outputs to feed mixer
inputs. Recommended load
impedances: 1.0 kohm.
GND/LIFTS:
GND position connects pin 1 of
INPUT/DIRECT OUTPUT to pin 1 of
ISOLATED OUTPUT. LIFT position
“floats” ISOLATED OUTPUT. Used to
reduce hum and buzz by eliminating
ground loops and providing proper
grounding for various conditions.
MS-3/082492
PRO CO SOUND, INC./135 E. KALAMAZOO AVE./KALAMAZOO, MI 49007 USA PRO CO

PRO CO MODEL MS-3 MIC SPLITTER
TYPICAL PERFORMANCE
All measurements made with 150 ohm source feeding INPUT
and 1.0 kohm loads on ISOLATED OUTPUTS to simulate typical
“real world” microphone and mic preamps. 0 dBv ref. = .775 volt.
FREQUENCY RESPONSE:
20 Hz-20 kHz, +/- .25 dB @ -15 dBv output.
-3 dB @ approximately 140 kHz.
TOTAL HARMONIC DISTORTION:
Less than .03% 20 Hz-20 kHz @ -30 dBv output.
Less than .1% 30 Hz-20 kHz @ -15 dBv output.
Less than .25% 20 Hz-20 kHz @ -15 dBv output.
PHASE RESPONSE:
Less than -13 degrees @ 20 kHz (ref. 1.0 kHz).
RISE TIME:
Less than 2.4 microseconds (2.0 kHz square wave, 10%-90%).
INPUT IMPEDANCE:
Greater than 570 ohm @ 1.0 kHz.
Greater than 570 ohm @ 10 kHz.
Nominal source impedance is 150 ohm.
OUTPUT IMPEDANCE:
Less than 255 ohm @ 1.0 kHz.
Less than 270 ohm @ 10 kHz.
Nominal load impedance is 1.0 kohm.
ENGINEERING SPECIFICATIONS
The microphone signal splitting unit shall be suitable for interfacing
one (1) balanced or floating low-impedance (150 ohm nominal)
microphone or similar signal source to three (3) balanced or floating
low-impedance (1.0 kohm nominal) microphone preamplifier inputs.
There shall be a 3-pin female XLR-type connector for input from the
source. There shall be a parallel or direct output from a 3-pin male
XLR-type connector. There shall be two (2) transformer-isolated lowimpedance outputs from 3-pin male XLR-type connectors. The
transformer shall be a Pro Co MBT-2 Microphone Bridging
Transformer. The primary electrostatic shield shall be connected to pin
1 of the source input and direct output connectors. The secondary
electrostatic shields shall each be connected to pin 1 of their respective
transformer-isolated XLR outputs. There shall be a ground-lift switch for
each isolated output to allow the secondary shields to be connected to
the primary shields or isolated as required.
The enclosure shall be constructed in the Pro Co “Uni-box™”
design with 16-gauge steel black zinc finish top and bottom plates,
16-gauge black texture powder coated steel end plates and black
anodized aluminum side channels. Control functions shall be identified
by a printed Lexan® top panel overlay. Switches shall be of the
miniature “rocker” type and shall be recessed. The enclosure shall be
provided with two (2) miniature handles at each end (front and back)
and four (4) non-conductive feet. The dimensions of the unit shall be
4.875" D x 4.375" W x 1.75" H
The microphone signal splitting unit shall be a Pro Co Monoface
MS-3 Mic Splitter.
THE PRO CO MBT-2 TRANSFORMER
(123.8mm D x 111.1mm W x 44.4mm H).
VOLTAGE LOSS:
Less than 2.5 dB @ 1.0 kHz.
MAXIMUM INPUT LEVEL FOR 1% THD:
0 dBv @ 20 Hz.
+4 dBv @ 30 Hz.
+8 dBv @ 50 Hz.
NOTE: Phantom power (if required) must be supplied by mixer
(or suitable power supply) connected to DIRECT OUTPUT.
PRO CO MODEL MS-3
VIO/WHT
BRN
INPUT
DIRECT
OUTPUT
1
2
3
1
2
3
WHT
YEL
BLK/WHT
MBT-2
TFMR
RED
BLK
GRN
BLU/WHT
GND
LIFT
GND
LIFT
The MBT-2 is a carefully designed, custom-built 1:1:1
microphone bridging transformer whose characteristics are optimized
for use with balanced low-impedance microphones or similar sources.
Special winding techniques and a high-permeability (80% nickel)
core lamination preserve full frequency response while minimizing
signal losses and other “loading” effects. Separate electrostatic shields
for primary (input) and each secondary (output) winding reduce
capacitive coupling of ground-borne electrical noise between main,
stage monitor and recording or broadcast feed mixers, eliminating
annoying 60-Hz hum and buzz. The source impedance of the MBT-2 is
very similar to that of a low-impedance microphone to ensure proper
matching to the input circuitry of the mixers. The result is clean
transient response (no overshoot or ringing) and low distortion even at
low frequencies and high input levels.
1
ISOLATED
2
OUTPUT 1
3
1
ISOLATED
2
OUTPUT 2
3
DIMENSIONS
105.2mm
4.14"
4.375"
111.1mm
WEIGHT.......1.125 lb.
0.51 kg.
SHIPPING
WEIGHT.......2.0 lbs.
0.91 kg.
4.875"
123.8mm
1.75"
44.4mm
PRO CO SOUND, INC./135 E. KALAMAZOO AVE./KALAMAZOO, MI 49007 USA PRO CO